1. Field of the Invention
This invention relates to an apparatus for solving manufacturing issues related to casting panels for use in the fields of industrial design and architecture. A reconfigurable and reusable flexible membrane mold is disclosed that can be selectively and accurately configured for casting panels and the like into a variety of different sizes and shapes.
2. Background Art
Software today has enabled designers to develop virtually any surface regardless of complexity and variability of curvature. Moreover, manufacturing has, for all intents and purposes, allowed the designer to realize these designs in physical artifact while presenting few limitations other than cost. We live in an age where population will exceed nine billion by 2050. Resources are becoming scarce and expensive, energy consumption is rising, and jobs are a welcome commodity globally. The building industry accounts for about half the world's consumption of energy which mandates that architects and engineers design sustainably. One of the most notable groups pushing for high performance sustainable design is the 2030 Challenge which asks the building industry to cut energy use in buildings by 50% by 2030. The program has since extended this challenge not only to the performance of buildings but the manufacturing and construction of buildings.
Computer Numeric Control (CNC) routing or hot wire foam cutting is the current industry standard for producing molds for casting objects that display smooth variable geometry. This method uses stock material that comes in sheet or block units and removes material until the final part is revealed in a process commonly known as subtractive manufacturing. This process typically utilizes a routing bit of various sizes and shapes or a hot wire to cut down the material. The resulting parts are precise, accurate, and relatively smooth. However, the process is both time consuming and wasteful with respect to material. A typical process for producing one panel would start with a three dimensional Computer Aided Drawing (CAD) surface that is exported into a Computer Aided Manufacturing (CAM) program. The CAM program will then write G-Code which is a series of movements and cut commands encoded as a computer language that the CNC tool understands as its series of steps to realize the final part. Once the G-Code is produced, it is uploaded to the post-processing program of the CNC machine. The machine will then complete a series of cutting steps during which it removes one layer of material at a time until a rough form emerges to produce the part. This rough part is then subjected to a finishing cut process that reveals the final part. As the machine cuts down the stock material, the excess is turned into dust, flakes, or smaller particles which are collected via vacuum and disposed of as waste. Upwards of 90% of a stock material can be cut away as waste to reveal the final part depending on the relief depth of the part. The process of producing the G-Code, loading up stock material, cutting down the material, and finishing the part is very time consuming and wasteful.
Another process for manufacturing panels is Pin-Point forming (PPF) which was invented in 1923 by C. J. Williams and T. Skinner. This process uses a two-dimensional former to produce manually-adjustable automobile leaf springs. About twenty years thereafter, this method of forming was expanded to three dimensions by adding multiple rows with the intent of forming sheet metal. These types of forming devices are referred to in the art as reconfigurable discrete dies. Such devices were not capable of being digitally actuated until the mid-1970's following work performed by Professor David Hardt at the Massachusetts Institute of Technology (MIT). Professor Hardt's original design was a press that configured itself by adjusting a matrix of densely packed quarter inch pins with rounded heads via servo actuators. The configuration of the pins is actuated into its final position via input from a CAD surface whose typography is broken down into a height-field of lines where length is translated into servo motor rotational degrees or stepper motor steps. These machines are referred to as digitally reconfigurable formers which allow molds to be produced in one step by turning CAD data into physical form. This technique requires no stock material and no CAM programming or G-Code production which advantageously creates no waste. Once the panel is produced, the pins reconfigure to their original rest state and the process can be repeated for any other configuration. Various types of pin point formers have been developed throughout the years aimed at pressing sheet metal or thermoforming panels directly onto the array of pins.
The disadvantage of these conventional formers and processes is that one cannot cast materials against an open array of pins, because the casting material will destroy the mechanism. Therefore, it would be desirable to be able to overcome this disadvantage by attaching a flexible impervious membrane onto the ends of these pins that allow one to cast objects of variable geometry and depth.